System for controlling the clutch torque of an electromagnetic clutch for vehicles

Abstract

A system for controlling clutch torque for a vehicle which has a transmission and an electromagnetic clutch provided between an engine and the transmission, the clutch current being increasing with increase of engine speed. The system comprises an engine speed sensor for sensing the speed of the engine and for producing an engine speed signal in proportion to the engine speed, and an acceleration detecting switch for producing an acceleration signal. A vehicle speed detecting unit is provided for sensing the vehicle speed and for producing an output when the vehicle speed reaches a predetermined value at a low engine speed. A clutch current control unit is provided to respond to the output of the vehicle speed detecting unit and to the acceleration signal for increasing the clutch current along at an inclination up to a rated current.

What is claimed is: 
     
       1. In a system for controlling clutch torque of an electromagnetic clutch for a vehicle having an engine and a transmission, the electromagnetic clutch being operatively connected between the engine and the transmission and being supplied with clutch current which increases with increasing of engine speed, the improvement comprising first means for sensing the speed of the engine for producing an engine speed signal as a function of the engine speed,   acceleration detecting means for producing an acceleration signal,   vehicle speed detecting means for sensing speed of the vehicle and generating an output when the vehicle speed exceeds a predetermined value, and   second means responsive to said output of said vehicle speed detecting means and to said acceleration signal for increasing the clutch current up to a rated current of the clutch at a rate smaller than a rate which is determined by engine speed at the generation of the output of the vehicle speed detecting means.   
     
     
       2. The system according to claim 1 wherein said first means comprises an engine speed sensor and a engine speed current generating means responsive to the output of the engine speed sensor for producing the engine speed signal. 
     
     
       3. The system according to claim 2 wherein said first and second means comprises a microcomputer. 
     
     
       4. The system as set forth in claim 1, wherein said second means is responsive as set forth, further when an immediately previously sensed vehicle speed is lower that said predetermined speed.   
     
     
       5. The system as set forth in claim 1, wherein said acceleration detecting means is a switch.   
     
     
       6. The system as set forth in claim 1, wherein said first means produces said engine speed signal in proportion to the engine speed.   
     
     
       7. The system as set forth in claim 1, further comprising third means including a look-up table for providing increments of increasing clutch current responsive to said engine speed signal.   
     
     
       8. The system as set forth in claim 7, wherein said third means is inactivated when said second means becomes responsive as set forth.   
     
     
       9. The system as set forth in claim 1, wherein said inclination is linear.   
     
     
       10. In a system for controlling clutch torque of an electromagnetic clutch for a vehicle having an engine and a transmission, the eletromagnetic clutch being operatively connected between the engine and the transmission and being supplied with clutch current which increases with increasing of engine speed, the improvement comprising first means for sensing the speed of the engine for producing an engine speed signal as a function of the engine speed,   acceleration detecting means for producing an acceleration signal,   vehicle speed detecting means for sensing speed of the vehicle and generating an output when the vehicle speed exceeds a predetermined value, and   second means responsive to said output of said vehicle speed detecting means and to said acceleration signal for increasing the clutch current along a curve up to a rated current of the clutch to fully engage the clutch at the rated current, said curve having a smaller slope than that of said increasing current which is determined by engine speed at the generation of the output of the vehicle speed detecting means.